1. Field of the Invention
The present invention relates generally to inkjet printers and, in particular, to a method and structure for wiping and capping the printheads of one or more print cartridges. Most particularly, the invention relates to a method and structure that depend upon printer carriage motion for automatic wiping and capping of each printhead, that utilizes uni-directional, separate wiping action for each printhead, that caps each printhead with a constant capping force and that reduces noise associated with operation of the capping and wiping structure.
2. Related Art
Inkjet printhead nozzles commonly become plugged with ink blobs or particulate therein, or otherwise contaminated with internal bubbles that prevent them from operating properly. Lower print quality and user complaints often result. Conventional service mechanisms typically provide for the spitting, wiping and capping of single printheads, frequently require operator intervention and often take the printer off-line for several seconds. Wiping an inkjet printhead in two directions, or wiping multiple printheads with a single wiper surface, results in recontamination of a printhead during wiping or inter-printhead contamination.
Improved capping systems have been proposed that provide for constant-force, rather than constant-deflection, capping of plural printheads in inkjet printers. One such capping system is described in co-pending U.S. patent application Ser. No. 07/935,606, entitled "Ink-jet Printhead Cap Having Suspended Lip," filed on Aug. 26, 1992, and assigned to the assignee of the present invention. The disclosure of that co-pending patent application is incorporated herein by this reference.
Failure recovery methods and systems have been proposed that provide for the automatic recovery from a condition in a plural printhead inkjet printer in which the printhead's nozzles become clogged with ink and particulate, wherein the method includes capping the printheads, selectively priming and flushing a given printhead and then uncapping and wiping the printheads. One such method and system is described in copending U.S. patent application Ser. No. 07/949,318, entitled "Automatic Failure Recovery for Ink-jet Printheads," filed on Sep. 21, 1992, and assigned to the assignee of the present invention. The disclosure of that co-pending patent application also is incorporated herein by this reference.
Movement of a sled in a service station often results in impacts between the sled and surrounding parts of the printer. The impacts create undesirable levels of noise during operation of the printer.
Previously, wiper blades have been made of rubber. However, "shingling" of the wiper blades can result after prolonged used of the wiper blades, particularly in low humidity and low temperature environments. Shingling is a microscopic defect on the surface of the wiper blade that, during wiping, can cause air bubbles to be transmitted into the nozzles of the print cartridge. These air bubbles can cause ink to be displaced from the firing chamber of the print cartridge so that the print cartridges will not print, necessitating priming of the print cartridge in order to restore printing capability.
Additionally, in previous wiping systems, the wiper blades have been mounted below a surface of the sled and extended through a hole in the surface. Consequently, the wiper blades have been relatively long. As a result, the wiper blades have not been as stiff as desired. Generally, it is desirable to make the wiper blades as stiff as possible, without damaging the printhead, so that the most effective wiping will be obtained. This is particularly true for print cartridges containing black ink.